Vehicle headlight control circuit using an auxiliary contact on the dimmer switch

ABSTRACT

A solid state vehicle lighting control circuit having two control wires connecting the vehicle headlights to the foot dimmer switch and one control wire connecting the foot dimmer switch to the light switch which turns on the vehicle lights by grounding. A set of normally open contacts in parallel with the vehicle light switch is closed during actuation of the foot dimmer switch to illuminate the vehicle lights independently of the position of the vehicle light switch.

.United States Patent Ballou June 20, 1972 [54] VEHICLE HEADLIGHTCONTROL CIRCUIT USING AN AUXILIARY CONTACT ON THE DIMMER SWITCH [72]Inventor: Richard P. Ballou, Howell, Mich.

[731 Assignee: General Motors Corporation, Detroit,

Mich.

[22] Filed: Feb. 8, I971 [21] Appl.No.: 113,138

52 use. ..315/83, 200/865, 340/76 51 Int.Cl. ..B60ql/06 5s FieldofSelrch..315/82,83;200/86.5;340/76 [56] References Cited UNITED STATES PATENTS2,298,782 10/1942 Bluemle ..315/83 2,918,604 12/1959 Johnston ..315/823,139,555 6/1964 Paule et al 315/82 3,305,695 2/1967 Late ..315/823,355,624 11/1967 Guyton et al. ..3 l5/83 Primary Examiner-Roy LakeAssistant Examiner-Siegfried H. Grimm Attorney-Jean L. Carpenter andPaul Fitzpatrick [5 7] ABSTRACT A solid state vehicle lighting controlcircuit having two control I 2 Claims, 3 Drawing figures VEHICLEHEADLIGHT CONTROL CIRCUIT USING AN AUXILIARY CONTACT ON THE DIMMERSWITCH This invention relates to vehicle headlight control circuits and,more specifically, this invention relates to a headlight control circuitin which the foot dimmer switch actuates a switch in parallel with thevehicle light switch for illuminating the vehicle lights independent ofthe vehicle light switch.

Conventional headlight circuits use a light switch and a foot dimmerswitch in series with the vehicle lights which are energized when theheadlight switch is in an on position. Although this circuit performssatisfactorily when it is desired to continuously energize either thehigh or low beam filaments of the vehicle headlamps, it does not lenditself to momentary energization of either the high or low beamfilaments of the headlamps such as, for example, when it is desired touse the vehicle lights to attract the attention of the driver of animproperly approaching vehicle or to signal the vehicle immediatelyahead to move to the right lane to permit a legal passing.

It is the general object of this invention to provide a vehicle headlampcircuit which will allow the vehicle operator to energize the vehicleheadlamp filaments for any desired length of time independently of thevehicle light switch.

It is another object of this invention to provide for a vehicle headlamplighting circuit in which the vehicle headlamps may be energized by theactuation of the foot dimmer switch independently of the position of thevehicle light switch.

These and other objects of this invention may be best understood withreference to the following description of a preferred embodiment and theFigures in which:

FIG. 1 is a schematic circuit diagram of the preferred embodiment ofthis invention;

FIG. 2 is a schematic drawing of the modified foot dimmer switch whichis utilized in the preferred embodiment of this invention; and

FIG. 3 is a schematic drawing of a modified foot dimmer switchillustrating the invention with reference to a conventional vehiclelighting circuit.

Referring to FIG. 1, there is shown a vehicle headlamp lighting circuitfor energizing the left high beam filaments the right'high beamfilaments 12, the left low beam filament l4 and the right low beamfilament 16. A voltage source 18, which may be, for example, the vehiclebattery, is connected to the left and right high beam filaments l0 and12 through a pair of PNP transistors and 22 respectively, and to theleft and right low beam filaments l4 and 16 through a pair of PNPtransistors 24 and 26 respectively.

The base electrodes of the transistors20 and 22 are connected to anoutput terminal 28 of a dimmer switch 30 and the base electrodes of thetransistors 24 and 26 are connected to an output terminal 32 of thedimmer switch 30. The dimmer switch 30 also has an input terminal 34which is either connected to the output terminal 28 or the outputterminal 32 by a contact member 36.

The dimmer switch 30 is of the well-known variety and may take the formof the switch shown in the US. Pat. No. 3,041,429 which issued to H. V.Elliott on June 26, 1962. For the present time, it is sufiicient to saythat the contact member 36 alternately connects the input terminal 34 tothe output terminals 28 and 32 with each depression of the dimmerswitch.

The input terminal 34 is connected to a ground reference through a lightswitch 38. As can be seen, when the light switch 38 is closed, a groundsignal is supplied to either the tuating shell 46 which is biased in anupward position by a spring 48. The actuating shell 46 is mechanicallyassociated with the contact member 36 such that the contact member 36alternately connects the input terminal 34 to the output terminals 28and 32 with each depression of the actuating shell 46. As previouslyindicated, this form of dimmer switch is well known and, therefore, thespecific mechanical configuration will not be described in furtherdetail. The movable contact 44 is connected to the actuating shell 46and the stationary contact 42 is positioned relative thereto so thatupon the depression of the actuating shell 46, the contact 44 engagesthe contact 42. In addition, the actuating shell 46 is connected toground reference. Therefore, upon the depression of the actuating shell46 aground signal will be supplied to the input terminal 34 through thecontacts 42 and 44. The addition of these contacts can be made in anymanner known to those skilled in the art suited to the manufacturingprocess.

Referring to FIGS. 1 and 2, when the vehicle light switch 38 is open,the vehicle operator may yet energize the vehicle lighting circuit bydepressing the actuating shell 46 of the dimmer switch 30 to close thecontacts 42 and 44 and bias either the transistors 20 and 22 or thetransistors 24 and 26 into conduction to energize the high beamfilaments l0 and 12 or the low beam filaments 14 and 16 respectively. Byholding the actuating shell 46 in the depressed position, the vehicleoperator may maintain either the high beam filaments 10 and 12 or thelow beam filaments l4 and 16 in an energized condition. In addition, byperiodically depressing the actuating shell 46, the vehicle operator mayflash the vehicle headlamps, in which case the high beam filaments 10and 12 and the low beam filaments l4 and 16 would be alternatelyenergized.

One of the many advantages of the preferred embodiment as previouslydescribed is that if a ground should occur between the base of thetransistors and the dimmer switch or between the dimmer switch and thelight switch, the lights will be turned on rather than extinguished,since the headlamps are energized by supplying a ground signal. Inaddition, if an open circuit should occur between the dimmer switch andthe light switch, the vehicle lights may yet be energized by depressingthe actuating shell 46 of the dimmer switch 30.

The use of the transistors 20, 22, 24 and 26 reduces to a minimum thecurrent through the contacts of the dimmer switch 30 and the lightswitch 38. The same features could be obtained with the elimination ofthe transistors 20, 22, 24, and 26 by applying the potential from thevoltage source 18 to the headlamp filaments 10, 12, 14 and 16 at theirground terminals and connecting the remaining terminals to the dimmerswitch.

Referring to FIG. 3, there is shown the invention in conjunction with avehicle having a conventional headlight control system. In thisembodiment, the input terminal 34 of the dimmer switch 30 is connectedto the vehicle light switch 38 and to one terminal of a set of normallyopen contacts 50 output terminal 28 to bias the transistors 20 and 22into conduction to energize the left and right high beam filaments 10and 12 or the output terminal 32 to bias the transistors 24 and 26 intoconduction to energize the left and right low beam filaments l4 and 16.A high beam or low beam condition of the lighting circuit is selected bythe operation of the dimmer switch 30.

The input terminal 34 of the dimmer switch 30 is also connected toground through a circuit in parallel with the light switch 38 includinga normally open set of contacts 40 having whose remaining terminal isconnected to the voltage source 18. The set of normally open contacts 50are positioned relative to the actuating shell 46 so as to be closed byan insulated protrusion 52 on the actuating shell 46 when the actuatingshell 46 is depressed. As can be seen, the operation of this embodimentis similar to the embodiment with reference to FIG. 2.

The detailed description of the foregoing embodiments of the inventionfor the purpose of explaining the principles thereof is not to beconsidered as limiting or restricting the invention, since manymodifications may be made by the exerpreviously described cise of skillin the art without departing from the scope of the invention.

It is claimed:

1. A headlight control circuit for an automotive vehicle comprising, incombination, an automotive vehicle current source; high and low beamheadlamp filaments; a manually operable light switch; a headlamp beamcontrol switch having a manually operable member that is moved from aneutral position to an actuated position to switch from high to lowheadlight beam or visa versa; and switch means in parallel with thelight switch, the switch means being closed when the manually operablemember is moved out of the neutral position towards the actuatedposition, whereby the high or low beam headlamp filament, as the casemay be, is energized with each actuation of the headlamp beam controlswitch, the high or low beam headlamp filament being energized onlywhile the manually operable member is moved when the light switch isopen and the high or low beam filament being energized continuously atall positions of the headlamp beam control switch when the light switchis closed.

2. A headlamp control circuit for an automotive vehicle having a currentsupply, high and low beam headlamp filaments, a manually operable lightswitch and a manually operable headlamp beam control switch having twooutput terminals and an input terminal, the output terminals beingalternately connected to the input terminal with each actuation of theheadlamp beam control switch comprising, in combination, high beamcircuit control means connected to the current supply, the high beamheadlamp filaments and one of the output terminals of the headlamp beamcontrol switch, the high beam circuit control means being responsive toa grounding signal at the output terminal for energizing the high beamheadlamp filaments; low beam circuit control means connected to thecurrent supply, the low beam headlamp filaments and the other of theoutput terminals of the headlamp beam control switch, the low beamcircuit control means being responsive to a grounding signal at thelast-mentioned output terminal for energizing the low beam headlampfilaments; circuit means connecting the light switch between the inputterminal of the headlamp beam control switch and the ground potential;and switch means in parallel with the light switch, the switch meansbeing adapted so as to be closed while the headlamp beam control switchis actuated, the light switch and the switch means each supplying agrounding signal to the input terminal of the headlamp beam controlswitch when closed, whereby the high and low beam headlamp filaments arealternately energized with each actuation of the headlamp beam controlswitch, the high or low beam headlamp filament being energized onlywhile the headlamp beam control switch is actuated when the light switchis open and the high or low beam filament being energized continuouslybetween actuations of the headlamp beam control switch when the lightswitch is closed.

t I I

1. A headlight control circuit for an automotive vehicle comprising, incombination, an automotive vehicle current source; high and low beamheadlamp filaments; a manually operable light switch; a headlamp beamcontrol switch having a manually operable member that is moved from aneutral position to an actuated position to switch from high to lowheadlight beam or visa versa; and switch means in parallel with thelight switch, the switch means being closed when the manually operablemember is moved out of the neutral position towards the actuatedposition, whereby the high or low beam headlamp filament, as the casemay be, is energized with each actuation of the headlamp beam controlswitch, the high or low beam headlamp filament being energized onlywhile the manually operable member is moved when the light switch isopen and the high or low beam filament being energized continuously atall positions of the headlamp beam control switch when the light switchis closed.
 2. A headlamp control circuit for an automotive vehiclehaving a current supply, high and low beam headlamp filaments, amanually operable light switch and a manually operable headlamp beamcontrol switch having two output terminals and an input terminal, theoutput terminals being alternately connected to the input terminal witheach actuation of the headlamp beam control switch comprising, incombination, high beam circuit control means connected to the currentsupply, the high beam headlamp filaments and one of the output terminalsof the headlamp beam control switch, the high beam circuit control meansbeing responsive to a grounding signal at the output terminal forenergizing the high beam headlamp filaments; low beam circuit controlmeans connected to the current supply, the low beam headlamp filamentsand the other of the output terminals of the headlamp beam controlswitch, the low beam circuit control means being responsive to agrounding signal at the last-mentioned output terminal for energizingthe low beam headlamp filaments; circuit means connecting the lightswitch between the input terminal of the headlamp beam control switchand the ground potential; and switch means in parallel with the lightswitch, the switch means being adapted so as to be closed while theheadlamp beam control switch is actuated, the light switch and theswitch means each supplying a grounding signal to the input terminal ofthe headlamp beam control switch when closed, whereby the high and lowbeam headlamp filaments are alternately energized with each actuation ofthe headlamp beam control switch, the high or low beam headlamp filamentbeing eNergized only while the headlamp beam control switch is actuatedwhen the light switch is open and the high or low beam filament beingenergized continuously between actuations of the headlamp beam controlswitch when the light switch is closed.